This invention relates to a cylinder block for an internal combustion engine and more particularly to an improved, cylinder block casting having an integral pump cavity formed therein.
Frequently engine cylinder blocks are formed by a casting process and include one or more integrally formed pumping cavities that contain pumping elements for circulating a liquid necessary for the engine operation such as for a coolant pump. A typical arrangement of this type is shown in Japanese Published Application JP-A-2001-65354. As seen in this publication, the cylinder block has a cylinder block body having a plurality of cylinder bores formed along the axial length thereof that are surrounded by cooling jackets. The casing of a cooling pump for delivering coolant projects outwardly from a side of the cylinder block. By forming the pump body integrally with the cylinder block the construction in made simpler and as an added benefit, the cylinder block is strengthened as the integral pump adds to its rigidity.
However with the prior art structures of this type another problem arises. That is when the pump casing is formed integrally with the cylinder block body the horizontally extending passage communicating the pumping cavity with the communicating cylinder block cavity can form a trap that blocks the free passage of the molten metal during the casting process and voids can develop that may be difficult to detect. In any event, these voids can result in scrappage that adds to the cost.
It is therefore a principle object of the invention to provide a effective and sound casting for a cylinder block that incorporates an integral pump.
It is a further object of the invention to provide an integral cylinder block and pump having high rigidity.